Anastomosis instrument and method for performing same

ABSTRACT

A surgical instrument for anastomosis of first and second blood vessels includes a housing having distal and proximal ends, a handle and a disposable loading unit removably mounted to the distal end of the housing. The loading unit includes upper and lower fastener support members having a passage defined therethrough for receiving an end of the second blood vessel and configured to releasably support a plurality of surgical fasteners. The loading unit also includes a retractable anvil located at a distal end of the loading unit, the anvil being movable relative to the fastener support member in response to actuation of the handle to simultaneously deform the of surgical fasteners.

CROSS REFERENCE TO RELATED APPLICATIONS

[0001] This application is a continuation-in-part of U.S. applicationSer. No. 09/256,260, entitled “ANASTOMOSIS INSTRUMENT AND METHOD” whichwas filed on Feb. 23, 1999 by Nicholas et al., which is acontinuation-in-part of U.S. application Ser. No. 08/877,701, entitled“SINGLESHOT ANASTOMOSIS INSTRUMENT WITH DETACHABLE LOADING UNIT ANDMETHOD”, which was filed Jun. 17,1997 by Manzo et al., which applicationis a continuation-in-part of U.S. application Ser. No. 08/685,385,entitled “ANASTOMOSIS INSTRUMENT AND METHOD”, filed Jul. 23,1996 byHinchliffe et al., now U.S. Pat. No. 5,707,380, the entire contents ofall of these disclosures are hereby incorporated by reference.

BACKGROUND

[0002] 1. Technical Field

[0003] The present disclosure relates to a surgical instrument andmethod for performing anastomosis of tubular body structures, and moreparticularly to an instrument for joining vascular tissues, for example,during coronary artery bypass graft procedures.

[0004] 2. Background of Related Art

[0005] Coronary artery disease is often characterized by lesions orocclusions in the coronary arteries which may result in inadequate bloodflow to the myocardium, or myocardial ischemia, which is typicallyresponsible for such complications as angina pectoris, necrosis ofcardiac tissue (myocardial infarction), and sudden death. In some cases,coronary artery disease may be treated by the use of drugs and/or bymodifications in behavior and diet. In other cases, dilatation ofcoronary arteries may be achieved by such procedures as angioplasty,laser ablation, atherectomy, catheterization, and intravascular stents.

[0006] For certain patients, a coronary artery bypass graft (“CABG”) isthe preferred form of treatment to relieve symptoms and the graft oftenincreases life expectancy. A CABG procedure consists of directanastomosis of a vessel segment to one or more of the coronary arteries.For example, a reversed segment of the saphenous vein may be grafted atone end to the ascending aorta as an arterial blood source and at theother end to a coronary artery at a point beyond the arterial occlusion.Alternatively, the internal mammary artery (“saphenous vein ”) locatedin the thoracic cavity adjacent the sternum is likewise suitable forgrafting to a coronary artery, such as the left anterior descendingartery (“LAD”).

[0007] The performance of a CABG procedure typically requires access tothe heart, blood vessels and associated tissue. Access to the patient'sthoracic cavity may be achieved in an open procedure by making a largelongitudinal incision in the chest. This procedure, referred to as amedian stemotomy, requires a saw or other cutting instrument *to cut thesternum to allow the two opposing halves of the rib cages to be spreadapart to expose the internal organs of the thoracic cavity.

[0008] U.S. Pat. No. 5,025,779 to Bugge discloses a retractor which isdesigned to grip opposite sternum halves and spread the thoracic cavityapart. The large opening which is created by this technique enables thesurgeon to directly visualize the surgical site and perform procedureson the affected organs. However, such procedures that involve largeincisions and substantial displacement of the rib cage are oftentraumatic to the patient with significant attendant risks. The recoveryperiod may be extensive and is often painful. Furthermore, patients forwhom coronary surgery is indicated may need to forego such surgery dueto the risks involved with gaining access to the heart.

[0009] U.S. Pat. No. 5,503,617 to Jako discloses a retractor configuredto be held by the surgeon for use in vascular or cardiac surgery toretract and hold ribs apart to allow access to the heart or a lungthrough an operating “window”. The retractor includes a rigid frame anda translation frame slideably connected to the rigid frame. Lower andupper blades are rotatably mounted to the rigid frame and thetranslation frame respectively. The “window” approach enables thesurgeon to gain access through a smaller incision and with lessdisplacement of the ribs, and consequently, less trauma to the patient.

[0010] Once access to the thoracic cavity has been achieved, surgery onthe heart may be performed. Such procedures typically require that theheartbeat be arrested while maintaining circulation throughout the restof the body. Cardioplegic fluid, such as potassium chloride (KCl) isdelivered to the blood vessels of the heart to paralyze the rnyocardium.As disclosed in WO 95/15715 to Sterman et al. for example, cardioplegicfluid is infused into the myocardium through the coronary arteries by acatheter inserted into the ascending aorta.

[0011] Alternatively, cardioplegic fluid is infused through the coronaryveins in a retrograde manner by a catheter positioned in the interiorjugular vein accessed at the patient's neck. Such procedures require theintroduction of multiple catheters into the blood vessels adjacent theheart, which is a complicated procedure requiring that the desiredvessels be properly located and accessed. The progression of the guidewires and catheters must be closely monitored to determine properplacement. Furthermore, the introduction of catheters form punctures inthe blood vessels that must be subsequently closed, and there is anincreased risk of trauma to the interior walls of the vessels in whichthe catheters must pass.

[0012] Alternatively, the CABG procedure may be performed while theheart is permitted to beat. Such a procedure is now commonly referred toas minimally invasive direct coronary artery bypass (MIDCAB) whenperformed through a thoracotomy (when performed through a sternotomy,the procedure is commonly called open coronary artery bypass (OP-CAB). Asurgical instrument is used to stabilize the heart and restrict bloodflow through the coronary artery during the graft procedure. Specialcare must be given to procedures performed on a beating heart, e.g.synchronizing procedures to occur at certain stages in the cardiaccycle, such as between heartbeats.

[0013] To perform a CABG procedure, the harvested vessel segment, suchas the saphenous vein, is grafted to the coronary artery by end-to-sideanastomosis. Typically, sutures are used to graft the vessel segments.However, conventional suturing is complicated by the use of minimallyinvasive procedures, such as the window approach, e.g., limited accessand reduced visibility to the surgical site may impede the surgeon'sability to manually apply sutures to a graft. Additionally, it isdifficult and time consuming to manually suture if the CABG procedure isbeing performed while the heart is beating as the suturing must besynchronized with the heart beat.

[0014] As can be appreciated, the process of manually suturing theharvested vessel segment to a coronary artery is time consuming andrequires a great deal of skill on the part of the surgeon. The resultingsutured anastomosis will also be dependent on the skills of the surgeon.In minimally invasive procedures such as in MIDCAB, the ability tosuture is even more complicated due to limited maneuverability andreduced visibility. U.S. Pat. No. 5,707,380 to Hinchliffe et al., theentire contents of which are hereby incorporated by reference, disclosesan apparatus and a procedure that enable remote anastomosis withoutpiercing of vessels during both conventional and minimally invasiveprocedures.

[0015] A continuing need exists, however, for improved surgicalinstruments and methods for performing remote anastomoses during bothconventional and minimally invasive procedures.

SUMMARY

[0016] The present disclosure relates to a surgical instrument foranastomosis of first and second blood vessels which includes a housinghaving distal and proximal ends, a handle and a disposable loading unitremovably mounted to the distal end of the housing. The disposableloading unit includes upper and lower fastener support members having apassage defined therethrough for receiving an end of the second bloodvessel and configured to releasably support a plurality of surgicalfasteners and a retractable anvil located at a distal end of the loadingunit. The anvil is movable relative to the fastener support member inresponse to actuation of the handle to simultaneously deform thesurgical fasteners.

[0017] In one embodiment, the loading unit includes two halves which arepivotable relative to one another to release the second vessel after theinstrument is fired. Preferably, the fastener support member includesupper and lower fastener support members which support the fasteners inan array-like manner.

[0018] In another embodiment, the loading unit includes a firstretracting sleeve which moves the anvil in response to actuation of thehandle. Preferably, loading unit includes first and second retractingsleeves which are movable relative to the fastener support member from afirst position wherein the distal ends of the retracting sleeves aredisposed relative to the fastener support member to a second positionwherein the distal ends of the retracting sleeves are disposed in closerproximity to the fastener support member.

[0019] In another embodiment, an actuator moves the first and secondsleeves relative to the fastener support member. Preferably, continuedmovement of the handle moves the second sleeve relative to the firstsleeve.

[0020] In another embodiment, the distal end of the first sleeveincludes a plurality of elongated channels for supporting the surgicalfasteners. Preferably, each of the channels includes a distal andproximal end wherein each distal end is radially offset from theproximal end such that the proximal and distal ends of the surgicalfasteners are supported in a radially offset manner. It is envisionedthat the second retracting sleeve releasably retains the surgicalfasteners within the elongated channels and the anvil has an angledsurface such that the distal ends of the surgical fasteners deformproximally upon actuation of the handle.

[0021] In another embodiment the actuator includes a cam having morethan one cam follower. It is also envisioned that the cam may includemultiple stages for imparting different, independent and/or varyingmovement to each of the cam followers upon actuation of the handle.

BRIEF DESCRIPTIBN OF THE DRAWINGS

[0022] Other objects and features of the present invention will becomeapparent from the following detailed description considered inconnection with the accompanied drawings. It should be understood,however, that the drawings are designed for the purpose of illustrationonly and not as a definition of the limits of the invention.

[0023] An illustrative embodiment of the subject surgical instrument andmethod are described herein with reference to the drawings wherein:

[0024]FIG. 1 is a perspective view of a surgical instrument constructedin accordance with a preferred embodiment of the present disclosure;

[0025]FIG. 2 is an enlarged, partial perspective view of a single useloading unit (hereinafter “SULU”) constructed in accordance with apreferred embodiment of the present disclosure;

[0026]FIG. 2A is an enlarged, perspective view of the indicated area ofdetail of FIG. 2;

[0027]FIG. 3 is a perspective view of a surgical fastener which isdesigned for operative engagement with the SULU for creating vascularanastomosis between two luminal vessels;

[0028]FIG. 4 is a side view the surgical instrument of FIG. 1;

[0029]FIG. 4A is a left, side view of a handle/actuator assembly of thesurgical instrument of FIG. 1 shown without a cover plate attachedthereto;

[0030]FIG. 5 is an enlarged, perspective view of a distal end of theactuator assembly shown in a pre-loading position to receivingly engagethe SULU;

[0031]FIG. 6 is a reverse, perspective view of the SULU of FIG. 2;

[0032]FIG. 6A is a reverse, perspective view of a lower half of the SULUof FIG. 2;

[0033]FIG. 7 is a perspective view with parts separated of the SULU ofFIG. 2;

[0034]FIG. 7A is a greatly enlarged, perspective view of the indicatedarea of detail of FIG. 7;

[0035]FIG. 7B is a greatly enlarged, perspective view of the indicatedarea of detail of FIG. 7;

[0036]FIG. 7C is an enlarged, perspective view of a base portion of afirst retracting sleeve;

[0037]FIG. 7D is a greatly enlarged, perspective view of the indicatedarea of detail of FIG. 7C;

[0038]FIG. 8 is a greatly enlarged, perspective view of the indicatedarea of detail of FIG. 7;

[0039]FIG. 9 is a greatly enlarged, perspective view of the indicatedarea of detail of FIG. 7;

[0040]FIG. 10 is a perspective view of the actuator assembly with thecover plate shown separated;

[0041]FIG. 11 is a perspective view the actuator assembly of FIG. 10shown with parts separated;

[0042]FIG. 12 is a horizontal cross-sectional view of the surgicalinstrument of FIG. 1 shown loaded for firing;

[0043]FIG. 13 is a horizontal cross-sectional view of the indicated areaof detail of FIG. 12;

[0044]FIG. 13A is a greatly enlarged horizontal cross sectional view ofthe area indicated in detail of FIG. 13;

[0045]FIG. 14 is a top cross-sectional view of the surgical instrumenttaken along section line 14-14 of FIG. 12;

[0046]FIG. 15 is a greatly enlarged top cross-sectional view of the areaindicated in detail of FIG. 14;

[0047]FIG. 16 is a front cross-sectional view of the surgical instrumenttaken along section line 16-16 of FIG. 12;

[0048]FIG. 17 is a perspective view of the SULU with a first vesselinserted therethrough;

[0049]FIG. 18 is perspective of the SULU with an end of the first vesseleverted over a distal end of the disposable unit being inserted into anincision in a second vessel;

[0050]FIG. 19 is an internal, perspective view of the second vessel withthe SULU and the everted first vessel shown inserted therein;

[0051]FIG. 20 is a side cross-sectional view of the SULU and the evertedfirst vessel shown inserted within the second vessel in pre-firingposition;

[0052]FIG. 21 is a side view of the actuator assembly without the coverplate during a first firing stage of the instrument and showing theinternal movement of a first retractor within the actuator assembly;

[0053]FIG. 21A is a side cross-sectional view showing the relevantpositions of the internal working components of the actuator assemblyafter the first firing stage;

[0054]FIG. 21B is a side cross-sectional view showing the movement ofthe SULU during the first firing stage to deform the surgical fasteners;

[0055]FIG. 21C is a greatly enlarged side cross-sectional view of thearea indicated in detail in FIG. 21B;

[0056]FIG. 21D is a greatly enlarged perspective view of the surgicalfastener shown in a “stapled” configuration;

[0057]FIG. 21E is a side view showing the relevant movement of a lockingsleeve after the first firing stage;

[0058]FIG. 22 is a side cross-sectional view of the actuator assemblyduring the second firing stage and showing the internal movement of asecond retractor within the actuator assembly;

[0059]FIG. 22A is a side cross-sectional view of the SULU during thesecond firing stage and showing the movement of a second retractingsleeve which moves as a direct result of the movement of the secondretractor to release the surgical fasteners;

[0060]FIG. 22B is a greatly enlarged side cross-sectional view showingthe retracting movement of a finger-like retention prong which moves asa direct result of the movement of the second retractor;

[0061]FIG. 23 is a perspective view of the SULU showing the pivotablemovement of the two supports which open after firing to release thefirst vessel;

[0062]FIG. 24 is a view showing a completed anastomosis;

[0063]FIG. 25 is a view showing an operating “window” with the patient'sheart exposed;

[0064]FIG. 26A is a view showing the surgical fastener staple pattern ofthe instrument described with respect to FIGS. 1-26; and

[0065]FIG. 26B. is a view showing one possible alternative surgicalfastener staple pattern.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

[0066] Preferred embodiments of the surgical instrument and methoddisclosed herein will be described in terms of a coronary artery bypassprocedure wherein a vascular anastomosis is created by joining a sectionof a harvested vessel, e.g., the saphenous vein, to bypass an occlusionin a coronary artery, e.g., the left anterior descending artery (“LAD”)and/or aorta. Alternatively, the presently disclosed surgical instrumentmay also be utilized in performing anastomosis of other tubular luminalbody structures.

[0067] In the drawings and in the description which follows, the term“proximal”, as is traditional, will refer to the end of the apparatuswhich is closer to the user, while the term “distal” will refer to theend which is further from the user.

[0068] Referring now in detail to the drawing figures in which likereference numerals identify similar or identical elements, oneembodiment of the present disclosure is illustrated generally in FIG. 1and is designated therein as surgical instrument 10. Surgical instrument10 includes two principal components, namely, an actuator assembly 20and a disposable loading unit (“DLU”) or a single use loading unit(“SULU”) 100, which along with their internal working components,mechanically cooperate to deform a surgical fastener 260 to complete ananastomosis between two vessels, e.g., an saphenous vein 320 and an LADand/or aorta 310 (FIG. 21 B).

[0069] The particular surgical instrument 10 shown in the variousfigures is preferably designed to deform an array of surgical fastenerssimilar to fastener 260 shown in FIG. 3 which is generally L-shaped andincludes a base leg 264 and an upwardly extending support leg 262.Preferably, base leg 264 includes a distal end 269 which is sufficientlyshaped to penetrate the saphenous vein 320 and the LAD and/or aorta 310upon deformation of the surgical fastener 260. The upwardly extendingsupport leg 262 is attached to base leg 264 at a pivot point 265 andincludes an inwardly extending prong 267 disposed at its free enddesigned to penetrate the LAD and/or aorta 310 and secure surgicalfastener 260 in position after anastomosis. A convexity 263 projectsinwardly between the base leg 264 and the support leg 262 and ispreferably sufficiently dimensioned to cooperate with the base leg 264to retain the saphenous vein 320 against LAD and/or aorta 310 in fluidcommunication after anastomosis as will be explained in greater detailbelow with respect to FIGS. 21B and 24. It is envisioned that thesurgical fastener 260 can be arranged on the SULU in differentpatterns/arrays depending upon a particular purpose.

[0070] As best seen in FIGS. 1, 4, 10 and 11, actuator assembly 20includes a proximal end 24, a distal end 22 and a housing 26 definedtherebetween for storing the internal working components of the actuatorassembly 20. Preferably, a plate 90 covers the internal components ofthe actuator assembly 20 when assembled. More particularly, housing 26includes at least one mechanical interface 23 a which reciprocates witha corresponding mechanical interface 23 b (FIG. 10) disposed on coverplate 90 to matingly engage the two components 26 and 90.

[0071] Actuator assembly 20 also includes a handle 12 which initiatesfiring of the surgical instrument 10 and a spring-loaded thumb tab 30for loading the SULU 100 onto the actuator assembly 20 both of whichwill be explained in greater detail below. Preferably, handle 12 isprovided with an ergonomic surface which is contoured and configured tobe comfortably gripped by the hand of the user during operation of theinstrument.

[0072] Turning now to FIG. 11 which illustrates in detail the internalworking components of the actuating assembly 20 which are preferablyassembled and stored within housing 26. More particularly, the actuatingassembly 20 includes a torsion spring 70 which mounts about post 21which protrudes from housing 26. Spring 70 includes a lower arm 74 whichis biased against a lower portion of the housing and an upper arm 72which is biased against a rotating two-stage cam 60.

[0073] Handle 12 includes a bushing 19 which protrudes laterally fromthe proximal end of the handle 12 and pivotally engages a correspondingrecess 29 disposed within the proximal end 24 of housing 26 to allowpivotal movement of the handle 12 with respect to housing 26. Handle 12also includes a vertically extending slot 27 disposed at its proximalend 24 which receives the proximal end of a lever 16 which moves inconjunction with the handle 12. A pair of flanges 14 a and 14 bdownwardly extend from the handle 12 and receive lever 16 therebetween.A mechanical interface 11 a disposed on handle 12 engages acorresponding mechanical interface 11 b disposed on lever 16 to securethe lever 16 to the handle 12. Preferably, lever 16 has a first recess17 shaped to engage and control the movement of the cam 60 duringdownward movement of the handle 12, the purpose of which will beexplained in more detail with respect to FIG. 21A. Lever 16 alsoincludes a second recess 15 which helps to limit lateral movement of thespring 70 within housing 26.

[0074] As mentioned above, actuating assembly 20 also includes aspring-loaded thumb tab 30 which rests atop housing 26 within alongitudinally extending slot 28 disposed near the distal end 22thereof. As best seen in FIG. 10, slot 28 is formed by notches 18 a and18 b of the housing 26 and cover plate 90, respectively. Tab 30 includesthumb guide 35 which cooperates with a sliding sleeve 32 to facilitateproximal movement of the tab 30 for loading the SULU. A downwardlydepending flange 34 disposed on tab 30 engages a corresponding slot 33located in a mount 31 disposed atop the sliding sleeve 32. Preferably,sliding sleeve 32 includes a post 36 which is dimensioned to receive atension spring 38 thereon. Spring 38 is biased between a block 47disposed within housing 26 and a proximal edge 37 of sliding sleeve 32such that spring 38 biases sliding sleeve 32 to a distal-most positionproximate distal end 22. Preferably, a distal end 39 of sleeve 32 isarcuate or semi-circular and is dimensioned to slidingly engage acorresponding end 82 of a first retractor 80 to lock the SULU 100 withinthe actuator assembly 20 after the SULU 100 is loaded as will bediscussed in more detail below.

[0075] Actuator assembly 20 also includes first retractor 80 and asecond retractor 50 which each move by way of movement of the handle 12which, in turn, imparts movement to the two-stage cam 60. Firstretractor 80 includes distal and proximal ends 82 and 84, respectively,and is generally tubular in dimension with the exception of an elongatedfurrow 83 extending proximally from distal end 82 for slidinglysupporting sleeve 32. Retractor 80 also includes a slot 85 for receivinga pin 54 for affixing the retractor 80 to the cam 60 and another pair ofslots 87 and 89 located near the proximal end 84 for receiving two camfollowers 51 a and 51 b, respectively. Preferably, the proximal end 84is bifurcated to facilitate insertion of the second retractor 50therein.

[0076] As best seen in FIGS. 11 and 16, a guide 81 engages an elongatedrib 25 a in housing 26 and an elongated rib 25 b in cover plate 90 toslidingly mount the retractor 80 to housing 26. Guide 81 is dimensionedslightly longer than rib 25 a to permit proximal movement of the firstretractor 80 relative to the housing 26 upon activation of the handle12. Preferably, a protective tube 95 is telescopically disposed aboutthe first retractor 80 and moves in conjunction with the sliding sleeve32 by way of slot 96 which secures mount 31 of the sliding sleeve 32therein. It is anticipated that protective tube 95 also helps torestrict lateral movement of the first retractor 80 during retraction.Tube 95 also includes an elongated channel 97 which generally alignswith guide 81 located in the first retractor 80 to mount both componentsto ribs 25 a and 25 b.

[0077] It is contemplated that proximal movement of tab 30 will impartreciprocating proximal movement to the sliding sleeve 32 to exposecarriages 86 and 88 disposed within the first retractor 80 which aredesigned to receive a pair of first and second retracting sleeves 110and 120 (FIGS. 7-9) of the SULU 100. More particularly, and as best seenin FIG. 5, carriage 86 is generally circular in shape and is designed toreceive an outer lip 122 formed by the union of end 122 a and 122 b ofsecond retracting sleeve 120 of the SULU 100. Preferably, carriage 86 isdimensioned larger that the lip 122 so as to permit proximal movement ofthe second retracting sleeve 120 relative to the first retracting sleeve110 as will be explained in more detail with respect to FIG. 22A.Carriage 88 is likewise circular in shape and receives outer lip 112 ofthe first retracting sleeve 110.

[0078] Actuator assembly 20 also includes a handle lock 40 which restsatop the first retractor 80 and extends laterally between the housing 26and the cover plate 90. More particularly, handle lock 40 is mountedwithin slots 93 a and 93 b as best seen in FIG. 10. Handle lock 40includes a post 43 which receives a spring 45 for biasing handle lock 40against a ledge 49 of the housing 26 (FIG. 12). Handle lock 40 alsoincludes a pair of flanges 42 a and 42 b which align with flanges 14 aand 14 b disposed on handle 12. As shown best in FIGS. 21 and 22,downward movement of the handle 12 forces the handle lock 40 initiallydistally against spring 45 until flanges 14 a and 14 b clear flanges 42a and 42 b at which point spring 45 forces handle lock 40 proximally tolock flanges 42 a and 42 b atop flanges 14 a and 14 b and to lock handle12 in a downwardly disposed position. Preferably, flanges 42 a and 42 bdefine a slot 41 for receiving lever. 16 therebetween.

[0079] Actuator assembly 20 also includes a second retractor 50 whichincludes an elongated arm 52 having a key-like distal end 53 and aT-shaped heel section 56. Preferably, T-shaped heel section 56 attachesto a tension spring 55 disposed proximally thereof. Second retractor 50is preferably bifurcated at its proximal end forming two longitudinallyextending fins 58 a and 58 b each having a slot 57 and aperture 59 forreceiving cam followers 51 and 51 b, respectively. It is contemplatedthat spring 55 is biased against an elongated stop 65 which rests atoparm 52 and biases heel section 56 proximally when the second retractor50 is retracted which will be explained in more detail below withrespect to the operation of the surgical instrument 10.

[0080] As mentioned above, the first retractor 80 is affixed totwo-stage cam 60 by pin 54. More particularly, cam 60 includes anaperture 61 located near the distal end thereof for receiving pin 54which affixes the cam 60 to the first retractor 80. Cam 60 also includesa pair of generally vertical arcuately-shaped slots 62 and 64 which eachinclude two discrete stages, namely 62 a, 62 b and 64 a, 64 b,respectively, for imparting movement to corresponding followers 51 a and51 b. A nub 66 is located near the uppermost portion of the cam 60 andis dimensioned to slideably engage recess 17 located in lever 16 as bestillustrated in FIG. 12.

[0081] It is contemplated that during downward movement of handle 12,lever 16 will bias nub 66 downwardly such that nub 66 rides proximallyalong recess 17 and causes cam 60 to pivot downwardly about pin 54 asshown best in FIGS. 21A and 22. In turn, Followers 51 a and 51 b willride along slots 64 and 62 and cause the first and second retractors 80and 50 to move in a proximal direction which will be explained in moredetail below. Preferably, recess 17, nub 66 and slots 64 and 62 can bedimensioned to control the movement and timing of the cam followers 51 aand 51 b. For example, it is envisioned that the stages 64 a, 64 b and62 a and 62 b can be dimensioned to control the timing and movement ofthe first and second retractors which, in turn, can effect theefficiency of the anastomosis.

[0082] Elongated stop 65 is preferably affixed to the distal end of cam60 and rests atop the second retractor 50. Elongated stop 65 includes adistal end 69 and a proximal end 67 which includes two extendingportions 67 a and 67 b each having an aperture 63 a and 63 b,respectively, disposed therethrough. Preferably, end 69 of stop 65 issufficiently dimensioned such that it engages a corresponding biasingpost 102 located within the SULU 100.

[0083] Preferably, the second retractor 50, the cam 60 and the elongatedstop 65 are pre-assembled prior to insertion into the first retractor80. More particularly and as best illustrated in FIGS. 10-12, elongatedstop 65 is positioned atop arm 52 of the second retractor 50 betweenT-shaped heel section 56 and end 53. Apertures 63 a and 63 b of stop 65align with aperture 61 of cam 60 such that once the cam 60 and theelongated stop 65 are inserted within slot 91 of the first retractor 80,pin 54 locks the two components 65 and 60 together through slot 85.

[0084] Cam 60 is positioned between the extending fins 58 a and 58 b ofthe second retractor 50 such that, when the retractor 50 and cam 60 areinserted within slot 91 of the first retractor, followers 51 a and 51 bare inserted through slot 87 and slot 89, respectively, and slideablycouple the two components 50 and 60 within the first retractor 80.Handle lock 40 is then positioned atop the first retractor 80 asdescribed above. First retractor 80 is then mounted on ribs 25 a and 25b of housing 26 and cover plate 90, respectively and tab 30 along withsliding sleeve 32 are engaged thereon. Handle 12 and lever 16 are thenassembled as described above and pivotably mounted about post 21. Spring70 is then positioned accordingly so as to bias handle 12 againsthousing 26.

[0085] Turning now to FIGS. 7-9 which show an exploded view of theinternal working components of the SULU 100 which as mentioned aboveincludes first retracting sleeve 110 and second retracting sleeve 120which cooperate to deform fasteners 260 and securely fasten thesaphenous vein 320 to the LAD and/or aorta 310 in fluid communication asshown in FIG. 24.

[0086] More particularly and as best seen in FIGS. 7-7D, firstretracting sleeve 110 includes a tube-like base 110 a and an arcuatesleeve cap 110 b which together define the first retracting sleeve 110.Base 10 a includes a circular lip 112 located at its proximal end and asemi-circular anvil 118 a located at the opposite end. A locking tab 116a having an elongated slit 182 a located therein is disposed between lip112 and anvil 118 a. A longitudinally-extending slot 114 a is disposedbetween the lip 112 and the locking tab 116 a. At least one interface117 a downwardly depends from base 110 a to mechanically engage acorresponding mechanical interface 117 b disposed on sleeve cap 110 b(FIG. 7). A flange 113 a is preferably disposed beneath slot 114 a andis sufficiently dimensioned to engage corresponding flanges 13 b ₁ and113 b ₂ located on sleeve cap 110 b. Slot 114 a is sufficientlydimensioned to receive a tab 138 a (FIG. 13) which projects from anupper surgical fastener support 130 a which is explained in more detailbelow.

[0087] Sleeve cap 110 b includes a semi-circular anvil 118 b and abifurcated proximal end 113 composed of flanges 113 b ₁ and 113 b ₂which together define a slot 114 b for receiving a tab 138 b whichprojects from a lower surgical fastener support 130 b which is explainedin more detail below. Sleeve cap 110 b also includes mechanicalinterfaces 117 b which couples with corresponding mechanical interfaces117 a disposed on base 110 a to engage sleeve cap 110 b with base 110 a.A locking tab 116 b having an elongated slit 182 b located therein isdisposed between proximal end 113 and anvil 118 b. Alongitudinally-extending opening 111 b is preferably disposed proximatelocking tab 116 b and aligns with a corresponding opening 111 a in base110 a (FIG. 7C) such that the saphenous vein 320 can be receivedtherethrough as seen best in FIGS. 17 and 18.

[0088]FIGS. 2A and 7D show a greatly enlarged view of anvil 118 a whichincludes a semi-annular array of fastener support channels or cradles119 a each configured and dimensioned to support a surgical fastener 260therein. Sleeve cap 110 b also includes fastener support channels 119 bwhich, when base 110 a and sleeve cap 110 b are assembled, align to forma circular array about the internal surfaces of anvil 118 a and 118 b.It is envisioned that anvils 118 a and 118 b can be designed to supportdifferent arrays of surgical fasteners 260 depending upon a particularpurpose. Each channel 119 a and 119 b is preferably separated by ananchor 187 a and 187 b (FIG. 7) which releasably retains a projectingfinger 124 a, 124 b of second retracting sleeve 120 (FIG. 2A). Supportchannels 119 a and 119 b each include proximal ends 186 a and 186 b anddistal ends 184 a and 184 b which are radially offset from one anotherto seat surgical fastener 260 within channels 119 a and 119 b in aradially offset manner the purpose of which will be explained below withrespect to the operation of the surgical instrument 10. The distal end184 a of each channel 119 a is preferably arched so as to correspond tothe arcuate shape of the end of the surgical fastener 260 as best seenin FIG. 13A. It is anticipated that arching the distal end 184 a willcause the surgical fastener 260 to deform upwardly and proximally uponretraction of the first retracting sleeve 110 by the first retractor 80as explained below with reference to FIGS. 21-22.

[0089] FIGS. 7-7D also show second retracting sleeve 120 which includesan upper cuff 120 a, a lower cuff 120 b and an outer cap 128 whichtogether define the second retracting sleeve 120. More particularly,upper cuff 120 a includes a semi-annular lip 122 a at one end and aplurality of retention fingers 124 a at the opposite end. Upper cuff 120a also includes a first slot 101 which preferably aligns with slot 114 aof the first retracting sleeve 110 a to receive tab 138 a of upperfastener support 130 b therethrough (FIG. 20). A second slot 126 areceives locking tab 116 a when cuff 120 a is slideably mounted atopbase 110 a. Interfaces 129 a mechanically engage correspondinginterfaces 129 b located on lower cuff 120 b.

[0090] Lower cuff 120 b includes a bifurcated proximal end 107 whichcomprises flanges 107 b ₁ and 107 b ₂ which define a slot 108 forreceiving tab 138 b of lower fastener support 130 b therethrough and aplurality of retention fingers 124 b which extend from the opposite endthereof. A slot 126 b is disposed between the flanges 107 b ₁, 107 b ₂and the fingers 124 b for receiving locking tab 116 b of the sleeve cap110 b when cuff 120 b is slideably mounted thereon. Alongitudinally-extending opening 121 b is disposed proximate slot 126 band aligns with a corresponding opening 121 a in upper cuff 120 a andalso aligns with openings 111 a and 111 b of the first retracting sleeve110 such that the saphenous vein 320 can be received therethrough asseen best in FIGS. 17 and 18.

[0091] A semi-circular cuff cap 128 is disposed atop lower cuff 120 band mechanically interfaces with upper cuff 120 a such thatsemi-circular lips 122 a and 122 b for circular lip 122. Moreparticularly, cuff cap 128 includes a plurality of detents 123 b whichmechanically engage a corresponding plurality of notches 123 a locatedin upper cuff 120 a such that the cuff cap 128, upper cuff 120 a andlower cuff 120 b all move in unison upon retraction of the secondretracting sleeve 120. Sleeve cap 128 is preferably bifurcated at itsdistal end forming slot 109 which is dimensioned to receive tab 138 b.

[0092] As can be appreciated, fingers 124 a and 124 b move uponretraction of the second retracting sleeve 120 to release the surgicalfasteners 260 after firing. More particularly and as best seen in FIGS.2A and 7A, the distal end of each finger 124 a is forked and includes afirst prong 127 a which retains a surgical fastener 260 within thefastener support channels 119 a and a second prong 125 a whichinterlocks with anchor 187 a to releasably lock the finger 124 a to thefirst retracting sleeve 110 until released by the second retractor 50(FIGS. 22A and 22B) which will be explained in more detail with respectto the operation of the surgical instrument 10. Likewise, each finger124 b of lower cuff 120 b includes prongs 127 b and 125 b which operatesin the same manner.

[0093] As mentioned previously, the SULU 100 also includes fastenersupport 130 which has an upper support 130 a and a lower support 130 bwhich, when assembled, internally house the first and second retractingsleeves 110 and 120, respectively, along with their individual workingcomponents. Upper support 130 a and lower support 130 b each include adistal end 135 a and 135 b each having an array of braces 137 a and 137b, respectively, which project radially from distal ends 135 a and 135b. As best illustrated in FIG. 2, each brace 137 a and 137 b supports anupwardly extending support leg 262 of a surgical fastener 260 disposedwithin one of the channels 119 a or 119 b. A plurality of radiallyextending slots 139 a and 139 b are disposed between each support brace137 a, 137 b for retaining a surgical fastener 260 therein and forrestricting unwanted lateral =movement of each fastener 260. It isanticipated that each surgical fastener 260 is positioned within a slot139 a, 139 b such that convexity 263 projects outwardly from brace 137a, 137 b and, after anastomosis, cooperates with the base leg 264 toretain the saphenous vein 320 against LAD and/or aorta 310 (FIGS. 21Band 24).

[0094] Upper support and lower support 130 a and 130 b, respectively,also include hinges 136 a and 136 b which, when the SULU 100 isassembled, matingly engage one another to allow pivotable movementbetween the supports 130 a arid 130 b from an open position (FIG. 23) toa closed position (FIG. 2). Preferably, a pin 180 secures the two hinges136 a and 136 b together (FIG. 6). Upper and lower supports 130 a and130 b each include a longitudinally-extending opening 133 a (FIG. 23)and 133 b which aligns with openings 121 a, 121 b, 111 a and 111 bdescribed above to receive saphenous vein 320 therethrough as seen bestin FIGS. 17 and 18. Longitudinally oriented slots 131 a and 131 b aredisposed adjacent openings 133 a and 133 b on the upper and lowersupport members 130 a and 130 b, respectively, for receiving lockingtabs 116 a and 116 b in much the same manner as described above withrespect to slots 126 a and 126 b of the second retracting sleeve 120.

[0095] Lower support 130 b includes a pair of shoulders 132 a and 132 bdisposed on opposite sides of opening 133 b for slideably receiving acorresponding pair of flanges 144 a and 144 b associated with an upperlocking sleeve 140 a. More particularly, each flange 144 a and 144 bextends distally from the upper locking sleeve 140 a to define a notch149 a and 149 b, respectively, therein for receiving shoulders 132 a and132 b of lower support 130 b.

[0096] Upper locking sleeve 140 a includes a C-shaped clip 146 a (FIG.8) disposed therein which has pair of opposing hooks 147 a forsnap-lockingly engaging slit 182 a of locking tab 116 a of firstretracting sleeve 110. A lower locking sleeve 140 b operates in asimilar manner and includes a pair of opposing hooks 147 b forsnap-lockingly engaging slit 182 b of locking tab 1116 b of firstretracting sleeve 110. Upper locking sleeve 140 a also includes anopening 141 a which aligns with openings 133 a, 133 b, 121 a, 121 b, 111a and 111 b described above to receive saphenous vein 320 therethroughas seen best in FIGS. 17 and 18. It is envisioned that upon retractionof the second retracting sleeve 120, upper locking sleeve 140 a willmove proximally relative to shoulders 132 b and 134 b and disengageshoulders 132 a, 132 b which, in turn, will allow the upper and lowersupports 1130 a and 130 b to pivot about pin 180 and release thesaphenous vein 320 (FIGS. 21 E and 23). This will be explained ingreater detail with respect to the operation of the instrument asdescribed below.

[0097] SULU 100 also includes a biasing post 102 which mechanicallyaligns upper and lower supports 130 a and 130 b in fixed relationrelative to one another. More particularly, biasing post 102 includes aproximal end 103 and a distal end 105 and has a vertically orientedcavity 106 disposed therethrough for receiving tabs 138 a and 138 b ofthe upper and lower supports 130 a and 130 b, respectively. As mentionedabove, tabs 138 a and 138 b pass through slots 114 a, 114 b of the firstretracting sleeve 110 and through slots 101, 108 and 109 of the secondretracting sleeve 120 and mechanically align with one another withincavity 106 as best seen in FIG. 21B.

[0098] Biasing post 102 also includes a tapered spacer 104 disposedalong the outer periphery thereof for frictionally locking the firstretracting sleeve 110 in a retracted position after the first retractingsleeve 110 is withdrawn by the first retractor 80. More particularly,when the SULU 100 is assembled and prior to firing the surgicalinstrument 10, biasing post 102 is disposed relative to the firstretracting sleeve 110 such that spacer 104 is proximal to lip 112 (FIG.13). During retraction of the first retracting sleeve 110, lip 112 isforced over spacer 104 and the first retracting sleeve 110 is lockedinto retracted position and prevented from recoiling. As explained ingreater detail below, locking the first retracting sleeve 110 in aretracted position also pre-disposes the second retracting sleeve 120for retraction relative to the first retracting sleeve (FIG. 22A).

[0099] Turning now in detail to the loading of the SULU 100 withinactuator assembly 20 as best seen in FIG. 5, thumb tab 30 is movedproximally by way of thumb guide 35 against spring 38 which, in turn,moves sleeve 32 and protective cover 95 proximally to expose carriages86 and 88. The SULU 100 is then loaded within actuator assembly 20 byplacing lip 112 within carriage 88 and lip 122 within carriage 86. Asbest shown in FIG. 13, lip 122 is positioned near the distal end ofcarriage 86 which allows lip 122 and, hence, second retracting sleeve120, to move independently from the first retracting sleeve uponactivation of the second retractor 50. In contrast, carriage 88 isdimensioned smaller than carriage 86 such that lip 112 fits snuglywithin carriage 88. Once the SULU is positioned within carriages 86 and88, thumb tab 30 is released and spring 38 biases sleeve 32 andprotective cover 95 distally over lips 112 and 122 to lock the SULU 100within the actuator assembly 20.

[0100] In use and as shown in FIGS. 17-24, surgical instrument 10facilitates the performance of a vascular anastomosis and eithereliminates and/or minimizes the need for manual suturing of the vessels.The method and usage described herein will be addressed in terms ofvascular anastomosis performed on a beating heart. However, thepresently disclosed surgical instrument 10 may also be used inperforming anastomoses of other tubular or luminal body structureswithout departing from the scope of the present disclosure. For example,surgical instrument 10 may be used in conventional open CABG proceduresusing a median sternotomy or other large incision without stopping theheart. Alternatively, the thoracic “window” procedure may be used toachieve access to the heart. The “window” approach involves a smallerincision and less displacement of the ribs, and therefore is lesstraumatic to the patient. For this approach, conventional surgicaltechniques are used to determine the location of the incision to accessthe chest cavity.

[0101] To gain access to the heart, after an incision is made, asurgical retractor assembly may be used to separate the ribs at the siteof the incision as shown in FIG. 25. Specifically, a base 410 is placedon the chest of the patient with the central opening defined by the basebeing positioned over the operative site. Retractor assemblies 430 aremounted to the base 410 at various locations. Each retractor assembly430 includes a blade having a hook to engage either a rib or the sternumtherewith. The retractor assemblies are mounted and used to retract ribsuntil a sufficiently large opening in the chest cavity is defined toprovide direct access to the heart. For example, the sternum and thefourth and fifth ribs can be split apart to create a window. Otherconfigurations of spreading the ribs and/or selectively cuttingindividual ribs away from the sternum may also be utilized for aparticular procedure.

[0102] Once the desired access to the heart is achieved, the graftvessel, e.g., the saphenous vein 320 is dissected from the surroundingcartilage and muscle, and a free end of the vessel is exposed. Theoccluded coronary artery, e.g., the LAD and/or aorta 310, is thenprepared for receiving the saphenous vein 320 graft. The heart ispositioned in the desired orientation either by traction sutures passingthrough the pericardium or by manipulation with heart manipulationinstruments which are held by the surgical personnel or clamped in afixed orientation to a base such as the retractor assembly base. Bloodflow through the LAD and/or aorta 310 can be restricted bycardiopulmonary bypass and pericardial cooling. Alternatively, adampening instrument may be applied directly on the LAD and/or aorta 310to restrict blood flow and reduce movement of the heart near the LADand/or aorta 310.

[0103] Turning now in detail to the operation of the surgical instrument10 and in particular, the operation of the SULU 100 as detailed in FIGS.17-24, once the saphenous vein 320 has been harvested, the user insertsthe free end 322 into opening 133 of the SULU and pull via a surgicalhook or graspers the free end 322 towards the distal end of the SULU100. The user then everts the saphenous vein 320 over the anvils 118 a,118 b of the SULU 100 such that the free end 322 of the saphenous vein320 is retained by end 269 of the surgical fasteners 260. Everting ofthe saphenous vein 320 may be achieved by any suitable known instrumentsand/or techniques such as by using graspers.

[0104] In some cases it may be preferable to orient the upper and lowersupports 130 a and 130 b in a slightly longitudinally offset manner suchthat an angle is created relative to the transverse plane of the twosupports 130 a and 130 b in order to optimize the anastomosis and tofacilitate optimal blood flow across the graft site from the saphenousvein 320 to the LAD and/or aorta 310. This junction will create a moredramatically visible “heel” and “toe” effect in which an acute or obtuseangle between the vessels is clearly defined.

[0105] The remaining portion of the saphenous vein 320 is preferablypositioned away from the instrument 10 to facilitate insertion of thesaphenous vein 320 into the LAD and/or aorta 310 as shown in FIG. 18.The user then inserts the end of the SULU 100 into an incision 312 inthe LAD and/or aorta such that the distal end 269 of each of theplurality of fasteners 260 and the everted end portions 322 of thesaphenous vein 320 are sufficiently inserted into and through incision312 (FIGS. 19 and 20). As seen best in the enlarged view of FIG. 20, thesupport leg 262, convexity 263 and prong 267 of each surgical fastener260 remains outside incision 312. The instrument is now preset forfiring.

[0106] FIGS. 21-22 show the firing sequence of instrument 10, i.e., whenthe handle 12 is depressed by the user. As best shown in FIGS. 21 and21A, as handle 12 is depressed downwardly in the direction of referencearrow “A”, lever 16 simultaneously imparts movement to both handle lock40 and cam 60. More particularly, downward movement of handle 12 causesflanges 14 a and 14 b of lever 16 to urge flanges 42 a and 42 b ofhandle lock 40 distally against spring 45 in the direction of referencearrow “B” (FIG. 21). At the same time, handle 12 causes recess 17 oflever 16 to bias nub 66 which, in turn, causes cam 60 to deflectdownwardly and proximally as best seen in FIG. 21A. Preferably, recess17 in lever 16 is dimensioned to control the specific movement of nub 66within recess 17 which, in turn, controls the overall movement of cam60. Downward and proximal movement of cam 60 causes cam followers 51 aand 51 b to move within the first cam stages 64 a and 62 a of slots 64and 62, respectively, which, in turn, moves the first retractor 80 andprotective cover 95 proximally in the direction of reference arrow B′.

[0107] As seen best in FIG. 21, as retractor 80 moves proximally as aresult of the movement of cam followers 51 a and 51 b within slots 64and 62, slot 85 moves proximally until it abuts pin 54. Preferably, whenslot 85 abuts pin 54, cam 60 is forced more downwardly about pin 54 suchthat cam followers 51 a and 51 b move more proximally to engage thesecond stages 64 b and 62 b of the cam slots 64 and 62, respectively.

[0108] As mentioned above, the first retractor 80 retracts the firstretracting sleeve 110 (FIG. 21) which, in turn, causes surgicalfasteners 260 to deform as shown in FIGS. 21B and 21D. More particularlyand as best shown in FIG. 21 B, proximal movement of the first retractor80 causes both the first retracting sleeve 110 and the second retractingsleeve 120 to move proximally relative to biasing post 102 until biasingpost 102 abuts the end 69 of elongated stop 65. As a result, anvils 118a and 118 b deform the distal ends 269 of surgical fasteners 260upwardly and proximally towards braces 137 a and 137 b, respectively,i.e., arc-like distal ends 184 a and 184 b cause surgical fasteners 260to deform upwardly and proximally upon retraction of the firstretracting sleeve 110. At the same time, the LAD and/or aorta 310 isforced slightly proximally and extending prongs 267 penetrate to holdthe LAD and/or aorta 310 in position as best seen in FIG. 22A.

[0109] It is anticipated that the radially offset orientation of theopposite ends 186 a, 186 b and 184 a, 184 b of the support channels 119a and 119 b, respectively will cause the opposite ends 267 and 269 ofthe surgical fasteners 260 to deform at an angle a relative to oneanother as best shown in FIG. 21D. This allows end 269 to deformproximal to braces 137 a and 137 b. Preferably, braces 137 a and 137 bhave a tapered cross section to deform end 269 of surgical fastener 260radially from end 267 during deformation.

[0110]FIG. 21 C shows the resulting position of the spacer 104 of thebiasing post 102 after the first retractor 80 retracts the first andsecond retracting sleeves 110 and 120, respectively. More particularly,spacer 104 frictionally locks the first retracting sleeve 110 relativeto the second retracting sleeve 120 and prevents the first retractingsleeve 110 from recoiling after firing.

[0111]FIG. 21E shows the proximal movement of the locking sleeve 140 aas a result of the movement of the first retracting sleeve 110. Moreparticularly, when the first retracting sleeve 110 is retractedproximally, locking tab 116 a retracts within slot 131 a of support 130a and biases locking sleeve 140 a in a proximal direction as well asseen by reference arrow “C”. Proximal movement of the locking sleeve 140a relative to support 130 a disengages flanges 142 a and 144 a fromshoulders 132 b and 134 b, respectively, of support 130 b which, inturn, unlocks supports 130 a and 130 b from one another thus permittingpivotal movement of the support members 130 a, 130 b as best seen inFIGS. 21E and 23.

[0112] Continued downward movement of handle 12 results in both proximalmovement of the second retractor 50 and engagement of the handle lock 40with the handle 12. More particularly and as best illustrated in FIG.22, as the user continues to move the handle 12 in a downward direction,flanges 14 a and 14 b clear corresponding flanges 42 a and 42 b andspring 45 biases handle lock 40 proximally in the direction of referencearrow “D” to lock the handle 12 in position. Simultaneously, cam 60 isrotated about pin 54 to a point where the second stages 64 a and 62 a ofthe cam slots 64 and 62 effect the movement of the cam followers 51 aand 51 b. More particularly, as cam 60 is forced downwardly, the secondstage 62 a of cam slot 62 moves cam follower 51 b proximally which, inturn, moves the second retractor 50 proximally. The second stage 64 a ofcam slot 64 is generally vertically oriented and, as a result, camfollower 51 a moves vertically upon continued downward movement ofhandle 12. Slot 57 of retractor 50 allows the second retractor 50 toslide proximally relative to cam follower 51 a.

[0113] As mentioned above, second retractor 50 moves the key-like end 53of the second retracting sleeve 120 within carriage 86 relative to thefirst retracting sleeve 110 as illustrated by reference arrow “E” ofFIG. 22A. Proximal movement of the second retracting sleeve 120 retractsthe prongs 127 a and 127 b of fingers 124 a, 124 b, respectively, whichreleases the surgical fasteners 260 as illustrated by reference arrow“E” of FIG. 22B.

[0114] As mentioned above, after sleeve 110 is retracted, locking sleeve140 a moves proximally to allow the two supports 130 a and 130 b topivot away from one another as shown in FIG. 23 to permit the removal ofthe saphenous vein 320 from within the SULU thereby completing thevascular anastomosis as shown in FIG. 24.

[0115]FIG. 26A shows a schematic diagram of the surgical fastener staplepattern which is formed upon actuation of the instrument described abovewith respect to FIGS. 1-26. More particularly, the surgical fastenersare supported by the fastener support braces 137 a, 137 b in a normalmanner relative to a longitudinal axis “A” (FIG. 5) extending throughthe SULU. It is envisioned that other surgical fastener staple patterns,e.g., spiral, tangential or angular relative to axis “A”, may beutilized to achieve hemostasis between vessels, FIG. 26B.

[0116] It will be understood that various modifications may be made tothe embodiment shown herein. For example, the instrument may be sized toperform an anastomosis for other vessels and luminal tissue. Moreover,although the various internal components of the instrument 10 are shownengaged by particular mechanical interfaces it is envisioned that othertypes of mechanical interfaces can be employed to achieve the same orsimilar purpose, e.g., snap-fit, tongue and groove, press fit, etc.Therefore, the above description should not be construed as limiting,but merely as exemplifications of preferred embodiment. Those skilled inthe art will envision other modifications within the scope and spirit ofthe claims appended hereto.

What is claimed is:
 1. A surgical instrument for anastomosis of firstand second blood vessels, comprising: a housing having distal andproximal ends and a handle; a disposable loading unit removably mountedto the distal end of the housing having: upper and lower fastenersupport members having a passage defined therethrough for receiving anend of the second blood vessel and configured to releasably support aplurality of surgical fasteners; and a retractable anvil located at adistal end of the loading unit, the anvil being movable relative to thefastener support member in response to actuation of the handle tosimultaneously deform the surgical fasteners.
 2. A surgical instrumentaccording to claim 1 wherein the loading unit further comprises a firstretracting sleeve which moves the anvil in response to actuation of thehandle.
 3. A surgical instrument according to claim 1 wherein thefastener support member supports the fasteners in an array-like manner.4. The surgical instrument according to claim 1 wherein the distal endof the first sleeve includes a plurality of elongated channels forsupporting the surgical fasteners.
 5. The surgical instrument accordingto claim 4 wherein each of the channels includes a distal and proximalend wherein each distal end is radially offset from the proximal endsuch that the proximal and distal ends of the surgical fasteners aresupported in a radially offset manner.
 6. A surgical instrumentaccording to claim 1 wherein the anvil has an angled surface such thatthe distal ends of the surgical fasteners deform proximally uponactuation of the handle.
 7. A surgical instrument according to claim 4further comprising a second retracting sleeve for releasably retainingthe surgical fasteners within the elongated channels of the firstretracting sleeve.
 8. A surgical instrument according to claim 1 whereinthe loading unit further comprises second retracting sleeve which ismovable in response to actuation of the handle.
 9. A surgical instrumentaccording to claim 8 wherein continued movement of the handle moves thesecond retracting sleeve relative to the first retracting sleeve.
 10. Asurgical instrument according to claim 9 wherein movement of the secondretracting sleeve relative to the first retracting sleeve releases thesurgical fasteners.
 11. A surgical instrument according to claim 8wherein the second retracting sleeve includes a plurality of fingers forreleasably retaining the surgical fasteners against the anvil.
 12. Asurgical instrument according to claim 1 further comprising an actuatorwhich moves the first and second retracting sleeves in response tomovement of the handle.
 13. A surgical instrument according to claim 12wherein the actuator includes a cam.
 14. A surgical instrument accordingto claim 13 wherein the cam includes more than one cam follower.
 15. Asurgical instrument according to claim 13 wherein the cam includesmultiple stages.
 16. A surgical instrument for anastomosis of first andsecond blood vessels, comprising: a housing having distal and proximalends; a loading unit having: a fastener support member for supporting aplurality of surgical fasteners; first and second retracting sleeveswhich are movable relative to the fastener support member from a firstposition wherein the distal ends of the retracting sleeves are disposedrelative to the fastener support member to a second position wherein thedistal ends of the retracting sleeves are disposed in closer proximityto the fastener support member, and an actuator for moving the first andsecond sleeves relative to the fastener 13 support member.
 17. Thesurgical instrument according to claim 16 wherein the actuator includesa handle.
 18. The surgical instrument according to claim 16 wherein theloading unit is comprised of two halves which are pivotable relative toone another.
 19. The surgical instrument according to claim 18 whereinthe two halves of the loading unit when closed form an elongatedaperture for receiving the second vessel therethrough.
 20. The surgicalinstrument according to claim 16 wherein the distal end of the firstsleeve includes a plurality of elongated channels for supporting thesurgical fasteners.
 21. The surgical instrument according to claim 20wherein each elongated channel includes a distal and proximal endwherein each distal end is radially offset from the proximal end. 22.The surgical instrument according to claim 16 wherein the fastenersupport supports the surgical fasteners in an array-like manner.
 23. Thesurgical instrument according to claim 20 wherein the second sleeveincludes a plurality of resilient fingers which releasably secure thesurgical fasteners within the elongated channels.
 24. The surgicalinstrument according to claim 16 wherein continued movement of theactuator moves the second sleeve relative to the first sleeve.
 25. Thesurgical instrument according to claim 16 wherein the actuator includesa cam.
 26. The surgical instrument according to claim 16 wherein theactuator includes a multi-staged cam.
 27. The surgical instrumentaccording to claim 26 wherein a first stage of the multi-staged camimparts movement to both the first and second sleeves and a second stageof the multi-staged cam imparts movement to the second sleeve relativeto the first sleeve.
 28. The surgical instrument according to claim 16wherein the actuator includes at least one spring.
 29. The surgicalinstrument according to claim 16 further comprising a locking mechanismwhich locks the actuator to the housing after the instrument is fired.30. The surgical instrument according to claim 16 wherein the loadingunit is releasably mounted to the housing.
 31. The surgical instrumentaccording to claim 16 wherein the instrument further comprises a lockingtab for selectively mounting the loading unit to the housing.
 32. Thesurgical instrument according to claim 31 wherein the locking tab ismovable from a first position which enables the loading unit to bemounted to the housing to a second position which secures the loadingunit to the housing.
 33. The surgical instrument according to claim 16wherein the loading unit is disposable.
 34. The surgical instrumentaccording to claim 16 wherein the distal end of the first sleeveincludes an anvil for retaining the distal ends of the surgicalfasteners and for supporting an everted end of the second vessel. 35.The surgical instrument according to claim 34 wherein the anvil includesan angled surface which causes the distal end of the surgical fastenersto deform proximally during firing.
 36. A surgical instrument foranastomosis of first and second blood vessels, comprising: a housinghaving distal and proximal ends; a loading unit having: upper and lowerfastener support members for supporting a proximal end of a plurality ofsurgical fasteners in an array-like manner; first and second retractingsleeves disposed between the upper and lower fastener support members,the retracting sleeves being movable relative to the fastener supportmembers from a first position wherein the distal ends of the sleeves aredisposed relative to the fastener support member to a second positionwherein the distal ends of the sleeves are disposed in closer proximityto the fastener support members; an actuator for moving the first andsecond sleeves relative to the fastener support member.
 37. The surgicalinstrument according to claim 36 wherein the second sleeve is movablerelative to the first sleeve
 38. The surgical instrument according toclaim 37 wherein continued movement of the actuator moves the secondsleeve relative to the first sleeve.
 39. The surgical instrumentaccording to claim 38 wherein the housing includes a second key-like armfor moving the second sleeve relative to the first sleeve.
 40. Thesurgical instrument according to claim 36 wherein the first sleeveincludes a base and a sleeve cap, the sleeve cap being selectivelypivotable relative to the base.
 41. The surgical instrument according toclaim 36 wherein the second sleeve includes upper and lower cuffs, theupper cuff being disposed between the upper fastener support and thefirst retracting sleeve and the lower cuff being disposed between thelower fastener support and the first retracting sleeve.
 42. The surgicalinstrument according to claim 36 wherein each of the fastener supportmembers includes a plurality of radially inscribed channels forsupporting the proximal end of the surgical fasteners.
 43. The surgicalinstrument according to claim 36 wherein the distal end of the firstretracting sleeve includes a plurality of elongated channels forsupporting the surgical fasteners.
 44. The surgical instrument accordingto claim 43 wherein each elongated channel includes a distal andproximal end wherein the distal end is radially offset from the proximalend.
 45. The surgical instrument according to claim 43 wherein thesecond retracting sleeve includes a plurality of resilient fingers whichreleasably secure the surgical fasteners within the elongated channelsof the first retracting sleeve.
 46. The surgical instrument according toclaim 36 wherein the loading unit further comprises a post which uponmovement of the actuator bias the first and second retracting sleevesrelative to the fastener support members.
 47. The surgical instrumentaccording to claim 46 wherein the post further comprises a spacer forlocking the first retracting sleeve relative to the fastener supportmembers to permit subsequent movement of the second retracting sleeverelative to the first retracting sleeve upon continued movement of theactuator.
 48. The surgical instrument according to claim 36 wherein theloading unit is comprised two halves which are pivotable relative to oneanother.
 49. The surgical instrument according to claim 48 wherein thetwo halves of the loading unit when closed form an elongated aperturefor receiving the second vessel therethrough.
 50. The surgicalinstrument according to claim 49 wherein prior to actuation of thehandle, the two halves of the loading unit are pivotally securedrelative to one another and upon actuation of the handle, the two halvesare unsecured allowing the halves to pivot relative to one another torelease the second vessel from within the aperture.
 51. The surgicalinstrument according to claim 36 wherein the second retracting sleeveincludes a plurality of resilient fingers which releasably secure thesurgical fasteners within the elongated channels of the first retractingsleeve.
 52. The surgical instrument according to claim 36 wherein thesurgical fasteners are supported normally relative to a longitudinalaxis extending through the loading unit.
 53. The surgical instrumentaccording to claim 36 wherein the surgical fasteners are supported in anangular manner relative to a longitudinal axis extending through theloading unit.